1. Field of the Invention
The present invention relates to an on-vehicle navigation system, specifically to an on-vehicle navigation system, a route guide method, and a computer-readable recording medium capable of setting a detailed location regarding a destination or a way point, in correspondence with a specific proposed action at a destination or a way point, when the destination or the like is set.
2. Description of the Related Art
A typical on-vehicle navigation system generally includes a control unit such as a CPU that controls the entire process of navigation, a storage unit such as a CD-ROM or DVD-ROM to store map data, a display unit such as an LCD monitor, a GPS receiver that detects the current position of a vehicle, a gyroscope and speed sensor that detect the travel azimuth and travel speed of the vehicle, and so forth. Through the control unit, the navigation system reads out the map data including the current position of the vehicle from the storage unit, plots on the screen of the display unit a map image of an area that surrounds the current position of the vehicle based on the map data, superimposes a vehicle position mark that indicates the current position of the vehicle on the screen, scrolls the map image so as to follow the movement of the vehicle, and moves the vehicle position mark while immobilizing the map image on the screen, whereby a user can perceive at a glance where the vehicle travels.
The on-vehicle navigation system is also equipped with a guide function (route guide function) that helps the user to easily reach a destination without taking a wrong the road. According to this route guide function, the control unit searches an optimum route from a starting point (typically, the position of the vehicle) leading to a destination using the map data by performing a simulation by means of the breadth-first search method and/or the Dijkstra method and the map data, stores the searched route as a guide route, displays, while traveling, the guide route on the map image in a manner different from other roads (for example, by changing the color or thickening the line), and when the vehicle enters an area within a predetermined distance of an approaching intersection on the guide route, displays a guide map of the intersection (enlarged map of the intersection, an arrow indicating the travel direction at the intersection, a distance to the intersection, the name of the intersection, etc.), so that the user can perceive which road to travel, or which direction to take at the intersection.
To perform the route search function, the user sets in advance a destination, a way point(s) on the way to the destination, and several conditions (whether to give preference to a toll road or to give preference to an open road, whether to give preference to reducing the travel distance or to give preference to reducing the travel time, etc.) at the same time. On the basis of the data thus set, the navigation system searches plural guide routes to the destination or plural guide routes to the way point, and provides route guidance to follow one route that the user selects among them.
As a technique related to the above conventional technique, there is one disclosed in Japanese Patent Laid-Open No. 2001-331606, for example, wherein, when a user inputs an arrival and departure place of a vehicle, such as an airport, as a destination and selects a passenger transportation company (airline company), the navigation system notifies the user of a terminal corresponding to the passenger transportation company (the airline company). Further, in a technique disclosed in Japanese Patent Laid-Open No. H10-82652, the navigation system searches for a destination on the basis of the proposed action or conditions for such a proposed action based on the operator's input.